The glowing light from the Big Bang might actually be a physical wall marking the edge of a finite universe.
Most cosmologists believe the Cosmic Microwave Background (CMB) is just a leftover glow from billions of years ago. This theory suggests the CMB is the actual photonic surface or boundary of a finite, spherical cosmos. This model removes the need for mysterious dark energy to explain why the universe is expanding. It also does away with inflation, the idea that the universe exploded in size faster than the speed of light. If true, it means we live inside a bounded bubble rather than an infinite, stretching void.
The Spherical-Boundary Universe: A Vacuum-Driven Cosmology Where the CMB Defines the Photonic Surface of a Finite Expanding Cosmos
SSRN · 6593458
We propose a novel cosmological framework in which the Universe is a finite, spherically bounded luminous region expanding into an external vacuum devoid of matter, radiation, and spacetime curvature. In this model, the Cosmic Microwave Background (CMB) is reinterpreted not as relic radiation from a hot early phase, but as the photonic surface of the Universe itself: a boundary layer where radiation accumulates as the cosmos expands outward under the influence of an external vacuum-driven force.